The present invention relates in general to a locking mechanism for telescoping tubular members, and more particularly to a locking mechanism for telescoping tubular members of a carpet stretcher.
Extendible and retractable telescoping tubular members have been employed for increasing or decreasing the length of carpet stretchers.
The patent to Crain, Jr., U.S. Pat. No. 4,230,302, issued on Oct. 28, 1980, for Carpet Stretcher, discloses a carpet stretcher with extendible, telescoping tubular members. The telescoping tubular members are axially displaceable relative to one another to control the overall length of the tubular members. Radial, axially aligned openings are formed in the telescoping tubular members. By registering radial openings of the telescoping tubular members, spring loaded plungers enter the registered openings to lock the telescoping tubular members in an adjusted position. The plungers are depressed against the urgency of the spring and the telescoping tubular members are moved axially until a desired adjusted length is reached. Then, the plungers are released and one of the telescoping tubular members is moved axially relative to the other tubular member until the plungers enter the registered openings to lock the telescoping tubular members.
The patent to Parsons, U.S. Pat. No. 493,111, issued on Mar. 7, 1983, for Piano Stool, discloses a locking mechanism for telescoping tubes in which there is a spring loaded lever. One end of the lever is a plunger that enters registered openings of telescoping tubes for locking the telescoping tubes in an adjusted position. At the other end of the lever is an actuating rod. The rod is actuated to retract the plunger from the aligned holes. A fulcrum for the lever is disposed midway between the ends thereof.
In the patent to Ream, U.S. Pat. No. 3,752,440, issued on Aug. 14, 1973, for Carpet Stretcher Pivot Bridge, there is disclosed oppositely directed plungers for entering registered openings of telescoping tubes for locking the tubes in adjusted positions relative to one another. The plungers are spring loaded. In one instance, a bandtype spring is employed. In another instance, the plungers are mounted on opposite ends of a coil spring.
The patent to Payson, U.S. Pat. No. 4,076,213, issued on Feb. 28, 1978, for Locking Tube Assembly, discloses telescoping tubes. Disposed within a locking tube assembly is a locking collar that has a central aperture to receive an inner tube. A spring biases the collar to an oblique position relative to the axes for the telescoping tubes to lock the inner tube against retraction relative to an outer tube. The locking collar has a lug that projects through an axial slot in an axial tube and retains the outer tube in a fixed position with the locking collar. The locking collar has a lever oppositely located relative to the lug and projects through an axial slot in the outer tube. Actuation of the lever in the axial direction positions the locking collar radially relative to the axis of the telescoping tubes and releases the collar from locking engagement with the inner tube to enable the inner tube to be moved axially relative to the outer tube.
The patent to Stoll, U.S. Pat. No. 1,726,372, issued on Aug. 27, 1929, for Adjustable Chair, discloses telescoping tubes. A locking device for the telescoping tubes includes a locking lever that is spring loaded for engaging its end into registered openings of the tubes to lock the tubes in an adjusted position. The lever is located exteriorly of the telescoping tubes. A similar operating device is shown in the patent to Farren, U.S. Pat. No. 475,273, issued on May 17, 1982, for Road Cart.
In the patent to Richardson, U.S. Pat. No. 2,682,414, issued on June 29, 1954, for Longitudinally Adjustable Screw Driver, there is disclosed a handle movable relative to a tool shank. A spring loaded locking lever is pivotally mounted in the handle. At one end of the locking lever is a lug to enter an opening in the tool shank for locking the handle in an adjusted position on the tool shank. At the other end of the locking lever is an actuator shank that is depressed to remove the lug from the tool shank opening for moving the handle lengthwise along the tool shank.